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At least 577 records · Page 32Linked to original sources
PubMed2004

The distribution of drug-efflux pumps, P-gp, BCRP, MRP1 and MRP2, in the normal blood-testis barrier and in primary testicular tumours.

The drug-efflux pumps P-glycoprotein (P-gp) and multidrug resistance-associated protein 1 (MRP1) are present in the blood-testis barrier (BTB) and may hamper the delivery of cytotoxic drugs to the testis. The precise localisation of P-gp and MRP1 in testicular tissue and the presence of the efflux pumps MRP2 and breast cancer resistance protein (BCRP) in the BTB are unknown. We therefore studied the localisation of these pumps in the BTB in normal testis (n = 12), in non-seminoma (n = 10) seminoma (n = 10), and testicular lymphoma (n = 9). Slides were scored semi-quantitatively for P-gp, MRP1, MRP2 and BCRP and blood vessels with factor VIII antibody. In normal testis, P-gp and BCRP were strongly expressed by myoid cells and luminal capillary endothelial wall and P-gp also by Leydig cells. MRP1 was observed at the basal side of Sertoli cells and on Leydig cells. MRP2 was only weakly expressed by myoid cells. Seminomas and non-seminomas expressed P-gp and/or BCRP and/or MRP1, lymphomas strongly expressed P-gp, weakly expressed BCRP and did not or showed weak expression of MRP1. There was very little staining for MRP2 in the tumours. Newly formed vessels in all tumours only expressed P-gp and BCRP. P-gp, BCRP and MRP1 are present in different cell layers of the normal testis, suggesting the optimal protection of spermatogenesis. In germ cell tumours, this expression pattern may explain the chemoresistance observed to P-gp, BCRP and MRP1 substrates. In germ cell tumours and testicular lymphomas, P-gp and BCRP expression by tumour cells and by newly formed vessels may also contribute to chemoresistance. These findings underscore the importance of removing the affected testis in cases of primary germ cell tumours and testicular lymphomas, irrespective of whether the patient has already undergone chemotherapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2005

Variability in testis biopsy interpretation: implications for male infertility care in the era of intracytoplasmic sperm injection.

OBJECTIVE: To determine whether center to center discrepancies in the ability to locate sperm in infertile testes with abnormal histology stems in part from inconsistencies in pathologists' readings of testis biopsies. DESIGN: Prospective cohort study. SETTING: Academic male infertility practice. PATIENT(S): Consecutive series of azoospermic men referred with testis biopsy slides between 1998 and 2003. INTERVENTION(S): Testis biopsy histologies on azoospermic patients referred for infertility care were re-reviewed by a single pathologist blinded to the original reading. Subsequent infertility care was guided by the findings from the second histologic reading. MAIN OUTCOME MEASURE(S): Agreement between the outside and in-house review of testis biopsy readings was assessed with the kappa statistic. Pregnancy outcomes that resulted from clinical decisions informed by the second histologic readings were also assessed. RESULT(S): Among 113 histologic specimens, re-review was complicated by fixation artifacts in 18 cases (16%) and insufficient biopsy sample size in 13 cases (12%). The kappa score for interobserver agreement in readings was 0.43 (95% CI 0.32-0.054). Mixed histology patterns in particular were underappreciated by outside pathologists (13% of cases on original reading, 36% of cases on review). In 27% of all cases, the differences in biopsy readings had a significant impact on clinical management. CONCLUSION(S): A correlation between independent testis histology readings in azoospermic men demonstrates frequent inconsistencies. These differences contribute to inaccurate phenotyping of male infertility and can significantly impact the direction of infertility care. These findings highlight the need for a standardized approach to testis histologic review.

Adult↗
PubMed2006

Alterations in gene expression in the testis of angiotensin-(1-7)-receptor Mas-deficient mice.

The Mas protooncogene encodes a G-protein coupled receptor with seven trans-membrane domains and was recently described as a receptor for angiotensin-(1-7). Mas is highly expressed in testis and brain of rodents, whereas its expression in testis is localized to Leydig cells, being upregulated during puberty. Although the expression of this receptor in testis is strongly ontogenetically controlled and cell type-specific, Mas-deficient mice are fertile. To identify genes of which the expression is affected by the deletion of Mas, we performed differential gene expression profiling. Testis-RNA of Mas-knockout mice on a C57Bl/6 background vs. testis-RNA of C57Bl/6 wild type mice were analyzed on an Affymetrix Murine Genome U74v2 GeneChip probing >12,000 transcripts. The microarray identified 67 transcripts, which were downregulated in Mas-deficient mice and 65 genes, which were upregulated. The analysis of 132 differentially expressed genes by a Gene Ontology Mining Tool revealed genes with activities in mitochondria being overrepresented in the set of significantly affected genes. For some selected genes, the results were verified by a specific real time PCR. Three of these genes, coding for proteins involved in mitochondrial function and steroidogenesis, become henceforth targets for our continuing search for the physiological function of Mas in testis.

3-Hydroxysteroid Dehydrogenases↗
PubMed2005

Developmental changes of heat-shock proteins in porcine testis by a proteomic analysis.

Heat-shock proteins (HSPs) are important in spermatogenesis. This study investigated developmental changes in the expression of major HSPs in porcine testis. The testis from five immature (mean age 2.9+/-0.1 months) and five mature boars (35.7+/-14.0 months) were examined. Two-dimensional polyacrylamide gel electrophoresis was conducted and proteins were identified by Western blotting and/or matrix-assisted laser desorption/ionization mass spectrometry. Moreover, the 90, 70, and 60 kDa HSPs, 70 kDa heat-shock cognate protein (HSC 70), tubulin, and actin were quantified on two-dimensional gels. Protein spots were quantified by densitometry, combined with a computer-assisted image analysis system. Immunohistochemistry was performed to analyze the expression pattern of major HSPs and beta-tubulin in testis. One isoform of HSP 90 (HSP 90 alpha), two isoforms of HSC 70 (HSC 70a and HSC 70c), one isoform of HSP70 (HSP 70e), and tubulin increased after sexual maturation (P<0.05). A testis-specific HSP70 (P70t) was markedly increased in the testes of sexually mature boars. Meanwhile, levels of actin and some isoforms of HSPs including 60 kDa HSP remained similar in both groups. These observations were further confirmed by immunohistochemistry; therefore, the upregulation of protein expression in the adult testis could be attributed to a higher level of protein expression and the number of cells that were HSPs-positive already resided in the immature testis. The differential expression of major HSPs suggested that they may be important in porcine spermatogenesis.

Actins↗
PubMed2005

Genotoxic consequences associated with oxidative damage in testis of mice subjected to iron intoxication.

While iron-induced testicular dysfunction has been demonstrated adequately, the mechanism(s) involved and the genotoxic implications are not fully understood. In order to understand the genotoxic effects of iron intoxication, initially induction of oxidative stress response in testis of adult albino mice (CFT-Swiss) was ascertained following administration (i.p.) of acute sub-lethal doses of iron dextran (ID). Subsequently, multiple sub-lethal doses (50, 100 and 200 mg/kg bw/day) were employed to characterize effects on lipid peroxidation (LPO) in testis (homogenates, microsomal/mitochondrial fractions), DNA damage and incidence of abnormal sperms. While acute doses of ID induced only a marginal increase in LPO response in testis at 24 h of administration, multiple doses elicited a moderate (30-40%) increase in LPO in whole homogenates and significant dose-related elevation in both mitochondrial (20-45%) and microsomal fractions (25-65%). This was associated with significant increase in DNA damage in the testis as evidenced by increased single strand breaks in a fluorimetric analysis of DNA unwinding (FADU) assay. Further, evidences of oxidative damage in testis was evident in terms of increased protein carbonyls and altered antioxidant enzymic activities. The genotoxic implications were investigated by quantification of the frequency of abnormal sperms sampled at specific periods during spermatogenetic cycle. Nearly three- to seven-fold increase in percent abnormal sperms among the ID treated males were evident during the first 3 weeks although the counts were unaffected. Interestingly, in a classical dominant lethal (DL) assay, mating of ID treated (100 mg/kg bw/day for 5 days) males sequentially for a period of 5 weeks with untreated females resulted in a significant increase in male-mediated dominant lethal type mutations (the frequency of dead implants) during the first 3 weeks only indicating a stage-specific effect on post-meiotic germ cells. These findings provide an account of the early oxidative damage in testis in vivo following exposure to low levels of iron which may be wholly or in part responsible for the genotoxic consequences observed in this model of iron overload.

Animals↗
PubMed2006

Management of neonates with large abdominal wall defects and undescended testis.

OBJECTIVES: To assess, in a retrospective study, the outcome of different treatment modalities in newborns with undescended testes secondary to large abdominal wall or diaphragmatic defects. Large abdominal and diaphragmatic defects are known to be associated with cryptorchidism, yet the reported incidence varies widely. METHODS: A total of 112 neonates with large abdominal wall or diaphragmatic defects were treated from 1981 to 2005. Of the 55 male patients in this series, 9 (16.4%) presented with abdominal testes and 4 had an extra-abdominal testis (7.3%). RESULTS: The 2 patients undergoing primary orchiopexy had testes of normal size and in the normal position at last follow-up. In one of these patients in whom the testis was brought down to the internal inguinal ring, spontaneous descent occurred and the testis on the affected side was normal. The other patient required additional surgery and had an atrophic testis at last follow-up. In 1 patient with severe concomitant malformations, primary orchiectomy was performed. The 4 patients who did not receive initial treatment all lost their testes owing to atrophy. CONCLUSIONS: The results of the present study have indicated that primary orchiopexy should be attempted in all cases of abdominal wall defects associated with abdominal cryptorchid testes because it yields better testicular salvage rates. In cases in which the spermatic cord is not long enough to place the testis into the scrotum, mobilization and fixation at the lowest site possible resulted in better outcomes than leaving the testis in the abdomen.

Abnormalities, Multiple↗
PubMed2002

Differential expression of Prx I and II in mouse testis and their up-regulation by radiation.

Testis is one of the most sensitive organs to ionizing radiation. The present study was designed to unravel the possible role of antioxidant proteins, peroxiredoxin I and II (Prx I and II) in the testis. Our results show that Prx I and II are constitutively expressed in the testis and their expression levels are decreased to some extent as the testis develops. Interestingly, immunohistochemical analysis revealed a preferential expression of Prx I and II in Leydig and Sertoli cells, respectively. Neither Prx I nor Prx II expression was obvious in the testicular germ cells including spermatogonia and spermatocytes. Ionizing radiation exerted oxidative stress on the testis and induced apoptosis primarily in the germ cells. When the irradiated testis was examined, the Prx system was found to be transiently up-regulated. Taken together, we suggest that the relative radiation-resistance of Leydig and Sertoli cells could be attributed in part to the antioxidant function of the Prx system in these cells.

Animals↗
PubMed1988

Embryology of the gonad with reference to special tumors of the ovary and testis.

The ovaries and testes have very similar development patterns until about the fourth month of embryonic life. A review of the similar development (until the fourth month) provides an explanation for the origin of tumors commonly associated with ovarian tissue appearing in the testis and vice versa. Embryonic surface epithelium gives rise to mesothelial tissue from which the common epithelial tumors arise in the ovary. Since these cells disappear from the testis when the tunica albuginea develops, this offers an explanation for the lack of common epithelial tumors in the testis. The embryonic gonadal tissue or sex cord epithelium and the primitive germ cells give rise to similar tumors in both the ovary and the testis. The extraembryonal tumors arise from the extraembryonal cells and trophoblastic cells, which give rise to the endodermal sinus tumors and choriocarcinomas, respectively. Since there is such a similarity in the development of the ovary and testis with the potential for residual cells to remain, an explanation is offered for the development of similar tumors in the ovary and the testis.

Female↗
PubMed2000

Microsurgical testis biopsy: a novel technique for retrieval of testicular tissue.

PURPOSE: In vitro fertilization with intracytoplasmic sperm injection has resulted in a dramatic increase in the need for diagnostic and therapeutic testis biopsies. We developed a microsurgical testis biopsy technique which allows identification of testicular vessels and individual seminiferous tubules. We compare the results of this technique to our prior series of nonmicroscopic biopsies. MATERIALS AND METHODS: A retrospective study of 226 consecutive patients who had undergone open testes biopsy with or without an operating microscope was performed. Between 1988 and 1994 standard open testis biopsy was performed without a microscope in 119 patients and a single sample of testicular tissue was taken. After 1994 microsurgical biopsy was performed under 6 to 25x magnification in 107 patients, nearly half of whom had multiple biopsies of each testis. The complication rates of the 2 procedures were compared. RESULTS: Scrotal hematoma required surgical drainage in 3 of the 119 standard testis biopsy cases and testis atrophy was noted in 1, for a total complication rate of 3.4%. There were no episodes of clinically detectable testicular atrophy or scrotal hematoma requiring surgical drainage in the 107 microsurgical biopsy cases (p<0.05). In 2 men the microscope allowed identification of larger tubules that contained sperm. CONCLUSIONS: Use of the operating microscope for testicular biopsy allows identification and avoidance of testicular vessels, minimizing complications. It also may allow selection of seminiferous tubules more likely to contain sperm.

Biopsy↗
PubMed1989

Surgical management of undescended testis: retrospective study of potential fertility in 274 cases.

To determine the fertility potential of men with an undescended testis a retrospective study was performed on 274 patients by evaluating sperm density and sperm motility, as well as histopathological findings of the seminiferous tubules. The patients, who had been treated surgically when they were 2 to 5 or 9 to 12 years old and who were examined when they were 18 to 39 years old, were divided into 4 groups: group 1 (61 patients) underwent bilateral orchiopexy, group 2 (149) underwent unilateral orchiopexy, group 3 (26) underwent unilateral orchiectomy and group 4 (38) received no surgical treatment for a unilateral undescended testis. Significant differences in the sperm density and motility were detected between group 1 (normal range 0 to 7 per cent) and group 2 or 3 (normal range 72 to 79 per cent), and between group 2 or 3 and group 4 (normal range 42 to 58 per cent). Histopathological differences were significant between group 1 or 2 (Johnsen's score count 6.06 to 6.11) and group 4 (4.72) for the affected side, and between group 2 or 3 (9.09 to 9.20) and group 4 (8.60) for the unaffected side. The results suggest that surgical treatment may not significantly ameliorate the fertility potential of patients with bilateral undescended testes. On the other hand, in patients with unilateral undescended testis an operation not later than at early puberty is advisable to maintain the spermatogenic function in the unaffected testis. It is suggested that some unknown factors relating to the highly impaired unilateral undescended testis may in some way inhibit function of the contralateral unaffected testis.

Adolescent↗
PubMed1988

Acquired undescended (ascended) testis: effects of human chorionic gonadotropin.

A total of 7 boys 4 to 10 years old was evaluated for undescended testes. All patients had been seen previously by a pediatric urologist and diagnosed as having a retractile testis. In fact 4 boys had undergone surgical correction of a contralateral undescended testis at an earlier date at which time the testis in question could be manipulated into the scrotum. Another boy was examined under anesthesia and the operation was canceled because the testis could be brought into the scrotum. Subsequently, on followup evaluation 2 to 8 years later the ipsilateral testis could not be manipulated into the scrotum. Of the boys 6 then were treated with a short course of human chorionic gonadotropin. Four patients had a positive response but in 3 the testis was undescended again at examination 6 months later. Of the boys 6 ultimately underwent orchiopexy. Boys with highly retractile testes require periodic examination until puberty to ensure that those testes do not ascend secondarily.

Abdominal Neoplasms↗
PubMed1988

Fetal and postnatal testis shows immunoprivilege as donor tissue.

We evaluated the immunogenicity of the testis by transplanting adult, postnatal, and fetal rat testicular tissue into outbred adult female and male rats for 10 days. Testis grafts were evaluated morphometrically and histologically, and selectively compared to renal grafts previously reported in part. Testis grafts from days 15 to 21 of gestation, and from three, nine, 12 and 15 days after birth showed an overall increase in growth, with maintenance of architecture and minimal lymphocytic infiltrate. In contrast, only fetal renal tissue from days 15 to 17 demonstrated an increase in growth with maintenance of architecture and minimal lymphocytic infiltrate; grafts from later in gestation grew only slightly and showed progressive deterioration in architecture with an increasing lymphocytic infiltrate. Fifteen day fetal testis grafts were also implanted for longer intervals up to 45 days. The fetal testis grafts implanted for 20 and 30 days showed an increase in size with maintenance of architecture and minimal lymphocytic infiltrate. The observed fetal and postnatal testis growth in the non-immunosuppressed adult host makes compelling further studies directed at determining those factors contributing to the decreased immunogenicity of this organ.

Age Factors↗
PubMed1984

The effect of testicular torsion on contralateral testis and the production of antisperm antibodies in rabbits.

It has been previously shown that unilateral testis torsion can cause disruptive anatomic changes in the contralateral testis of rats. This study was conducted to duplicate these findings in rabbits and analyze their serum for the production of the immunoglobulin G class of antisperm antibodies and determine whether the proposed immune response demonstrated by contralateral anatomic testis changes was mediated by these antibodies. New Zealand white rabbits were divided into 8 groups. One had a sham operation, 1 had testis biopsy, 3 groups had ligation of the right testicular vessels with subsequent orchiectomy in 2 groups at 36 and 72 hours, and 3 groups had 720-degree torsion of the right testis. Half of the animals were sacrificed after 4 weeks and the other half after 8 weeks. Contralateral histology was analyzed in all rabbits and only those with torsion showed abnormal tubular architecture and defective spermatogenesis. Detorsion at 36 hours and 96 hours did not protect against contralateral testis damage. No animal whose vessels were ligated, no matter what treatment protocol was employed, showed contralateral damage. All rabbit sera were tested for the presence of immunoglobulin G antiserum antibodies against a control rabbit that was a known antibody former, using an enzyme-linked immunosorbent technique. No experimental animal had detectable levels of antisperm immunoglobulin G when compared to controls. Three male rabbits who were converted to antisperm antibody formers by injection of sperm did not show anatomic changes in their testes.

Animals↗
PubMed2003

Exposure to the environmental estrogen bisphenol A differentially modulated estrogen receptor-alpha and -beta immunoreactivity and mRNA in male mouse testis.

We examined the effects of bisphenol A (0.5 microg/ml or 50 microg/ml) in the drinking water on estrogen receptor (ER) alpha and beta proteins and mRNA in the testis of young mice following 8-weeks of oral administration of bisphenol A utilizing immunohistochemistry and semiquantitative reverse transcription polymerase chain reaction amplification (RT-PCR). ER beta was clearly localized in the nuclei of spermatogonia and/or spermatocytes. ER beta immunopositive cell numbers per testis section were significantly decreased in the 50 microg/ml bisphenol A-treated group compared with control and the 0.5 microg/ml bisphenol A-treated group. The number of ER alpha positive cells in the testis was significantly lower than ER beta positive cells in control group. ER alpha immunopositive cell numbers per testis section were markedly increased in the 50 microg/ml bisphenol A-treated group compared with the control and the 0.5 microg/ml bisphenol A-treated group. ER beta mRNA expression was significantly decreased in the 50 microg/ml bisphenol A-treated group compared with the control and the 0.5 microg/ml bisphenol A-treated group. In contrast, ER alpha mRNA expression was markedly increased in the 50 microg/ml bisphenol A-treated group compared with the control and the 0.5 microg/ml bisphenol A-treated group. The existence of ER alpha and beta in the testis suggests that estrogens directly affect germ cells during testicular development and spermatogenesis, and differential modulation of ER alpha and beta in the testis could be involved in the effects of bisphenol A.

Animals↗
PubMedDate not supplied

Local regulation of T cell numbers and lymphocyte-inhibiting activity in the interstitial tissue of the adult rat testis.

The testis is an immunologically privileged site, and transplantation data suggest that this privilege may be enhanced in cryptorchidism. Although alphabetaT cells, which mediate and promote the immune response, have access to the normal testis, relatively little is known about these cells in the abdominally located testis. An increase in testicular lymphocyte-inhibiting cytokines has also been implicated in enhanced graft survival following the experimental induction of cryptorchidism. Consequently, T cell traffic and lymphocyte-inhibiting activity in testes of cryptorchid adult rats were examined in the following study. Numbers of alphabetaT cells and the cytotoxic CD8(+) T cell subset in the testis were unaffected following 1 month of cryptorchidism. In contrast, subcutaneous testosterone implants, which inhibit Leydig cell function through suppression of gonadotrophin secretion, reduced these parameters in both scrotal and abdominal testes. Testicular T cell numbers were positively correlated with the number of testicular resident macrophages, which also were reduced by subcutaneous testosterone implants. The concentration of lymphocyte-inhibiting activity in the testicular interstitial fluid was reduced by 80% in short-term (1 month) and longer-term (3 months) cryptorchidism. These data indicate that the T cell population, and in particular the CD8(+) T cell subset, in the rat testis is functionally related to the resident macrophages or Leydig cells. On the other hand, testicular lymphocyte-inhibiting activity does not appear to be a determinant of the number of testicular T cells, and may not be a major factor in the prolonged survival of certain grafts in the abdominal testis.

Animals↗
PubMed2002

The effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin on the antioxidant system in mitochondrial and microsomal fractions of rat testis.

The ability of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to induce oxidative stress in hepatic and some extrahepatic tissues of animals has been reported. The precise nature and mechanism of action of TCDD on the male reproductive system is not clear. In the present study, we have investigated the induction of oxidative stress in the testis of rat after exposure to low doses of TCDD. TCDD (1, 10, and 100 ng/kg body weight per day) was administered orally to the rat for 45 days. After 24 h of the last treatment the rats were killed using anesthetic ether. The weights of the testis, epididymis, seminal vesicles and ventral prostate decreased while the body weight remained unchanged in the rats administered with TCDD. Mitochondrial and microsomal fractions of the testis were obtained by the method of differential centrifugation. The activity of antioxidant enzymes such as superoxide dismutase, catalase, glutathione reductase, and glutathione peroxidase decreased significantly in the animals treated with TCDD in a dose-dependent manner in the mitochondrial and microsomal fractions of rat testis. The levels of hydrogen peroxide generation (H(2)O(2)) and lipid peroxidation increased in mitochondrial, and microsomal fractions of the testis. The results suggested that the low doses of TCDD elicit depletion of antioxidant enzymes and concomitant increase in the levels of H(2)O(2) and lipid peroxidation differentially in mitochondrial and microsomal fractions of rat testis. In conclusion the adverse effect of TCDD on male reproduction could be due to induction of oxidative stress.

Animals↗
PubMed1986

Paracrine control of the testis.

The mammalian testis is under the overall control of pituitary gonadotropins but the utilization of these signals to achieve normal testicular function involves complex local interactions between the Sertoli and germ cells, the Sertoli and peritubular cells, and the Sertoli and Leydig cells as well as local control of the testicular vasculature. These interactions serve two purposes: (1) to coordinate the functions of the three testicular compartments (seminiferous tubules, interstitium and the vasculature); and (2) to control the complex but orderly sequence of events that constitutes the spermatogenic cycle. This process, which involves multiplication, differentiation and translocation of the germ cells is organized into a sequence of stages, each of which is composed of a constant association of germ cells at four or five different stages of development. At each stage of the spermatogenic cycle, different events occur and the function of the Sertoli cells alters, probably in accordance with the changing requirements of the associated germ cells. As yet, our understanding of these many local events is extremely limited, particularly with respect to the identity of the hormones/factors involved in controlling the various processes. Our knowledge of paracrine control mechanisms in the testis is derived mainly from studies of the rat, but as the process of spermatogenesis is essentially the same in most mammals and involves the same sequence of events, then findings in the rat can probably be applied in general, if not in detail, to the human testis; the limited direct information available on the human testis supports this view. As most cases of infertility in men occur despite normal or raised serum gonadotropin levels and are characterized by the production of reduced or normal numbers of sperm, then it seems likely that malfunction of one or more of the intricate paracrine processes within the testis may be involved in the aetiology of idiopathic oligospermia. It is therefore argued that advances in our knowledge of the paracrine control of the testis should have major repercussions on our ability to understand, and eventually treat, idiopathic infertility in men, and also to induce infertility for contraceptive purposes.

Animals↗
PubMed1999

Prolactin receptor expression in the testis of the ram: localisation, functional activation and the influence of gonadotrophins.

The present study investigated the pattern and site of expression of the prolactin receptor gene in the testis of the seasonally breeding Soay sheep. In experiment 1, Northern blot analysis confirmed expression of the prolactin receptor gene in the testis which was encoded by RNA transcripts of approximately 3.6, 11.2, 12.6, and 14.1 kb. In situ hybridisation localised expression of the receptor within the interstitial and seminiferous tubule compartments of the testis and immunohistochemistry localised expression of the receptor to Leydig cells and to pachytene spermatocytes, round and elongating spermatids. In experiment 2, phosphorylation of Jak2, Stat1 and Stat5 proteins in response to prolactin was investigated by Western blotting following incubation of testicular samples with 100 ng/ml ovine prolactin. Jak2 and Stat1 phosphorylation were induced by prolactin within 10 min and Stat5 within 30 min. In experiment 3, intact and hypothalamo-pituitary disconnected (HPD) rams were transferred from a short to a long day photoperiod regimen for a period of 8 weeks. By week 8, testicular diameter had declined in intact rams (52.71+/-1.06 cm vs. 48.00+/-0.49 cm for weeks 1 and 8 after transfer respectively, P<0.01, n = 3) and increased in HPD rams (27.00+/-0.45 cm and 29.66+/-0.99 cm for weeks 1 and 8 after transfer respectively, P<0.05, n = 3). RT-PCR using RNA extracted from intact and HPD rams confirmed expression of the prolactin receptor in the testis of both groups. Immunohistochemistry localised prolactin receptor expression in Leydig cells and in pachytene spermatocytes, round and elongating spermatids of intact sheep testis. In HPD rams, prolactin receptor expression was localised in Leydig cells and germ cells which were arrested predominantly at the pachytene spermatocyte stage. These data demonstrate expression of functional prolactin receptors in the testis of Soay rams. The site and pattern of expression of the receptor gene suggest a role for prolactin in the regulation of steroidogenesis and spermatogenesis.

Animals↗