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Biomedical subjects

B S Setty

Publications and source records attributed to B S Setty.

At least 55 records · Page 3Linked to original sources

Antifertility agents. 38. Effect of the side chain and its position on the activity of 3,4-diarylchromans.

In a study of the effect of the substituent on the receptor binding affinity (RBA), estrogenicity, and antiimplantation (AI) activity in trans-3,4-diarylchromans, it has been found that demethylation of trans-2, 2-dimethyl-3-phenyl-4-[p-(beta-pyrrolidinoethoxy)phenyl]-7-methoxychroman (centchroman, 1) to the corresponding 7-hydroxy compound (7) results in a 20-fold increase in RBA (112%) without any appreciable change in AI activity. On the other hand, absence of the pyrrolidinoethyl group from the 4-phenyl residue (6) leads to a drop in both RBA and AI activity. A chain length of two to three carbon atoms and a pyrrolidino ring appear to be necessary for activity in these compounds. It has been found that while the trans isomers with the tertiary aminoalkoxy side chain in the para position of the 4-phenyl radical were the most active, in the corresponding cis-chromans and chromenes, analogues with this chain in the meta position were most active; the ortho substituted compounds of all these series were inactive. In 3-phenyl-substituted compounds, the trans isomer carrying the p-hydroxy substituent (33) was found to be the most active; the corresponding pyrrolidinoethyl ether (13) showed a lower order of activity. The implication of these observations on the mapping of the different subsites on the receptor has been discussed.

Animals↗

Effect of flutamide, a nonsteroidal antiandrogen on functional maturation of the epididymis of rat.

The effect of flutamide, a non-steroidal antiandrogen on the growth and secretory function of the epididymis of rat during transition from prepubertal age (35 days old) to puberty (50 days old) was investigated. The results showed that the antiandrogen interfered with the growth of all the genital organs accompanied by a marked reduction in the secretory function of the epididymis as revealed by lowered levels of sialic acid and glycerylphosphorylcholine. These findings are discussed in relation to our previous observations in adult rats.

Anilides↗

Zinc content of maturing spermatozoa in oestrogen treated rats.

Zinc content of spermatozoa collected from the caput and cauda portions of the rat epididymis was determined by atomic absorption spectroscopy. The results showed about 60% reduction in the spermatozoal zinc content by the time they reach the cauda epididymis. This reduction was inhibited in rats receiving micro dose oestrogen which induced 'functional' sterility. It appears that the fall in zinc content of spermatozoa during their transport in the epididymis is related to sperm maturation and that oestrogen treatment interferes with this reduction in sperm zinc content.

Animals↗

Zinc in the epididymal and vasal spermatozoa of rhesus monkey (Macaca mulatta).

Zinc level in maturing spermatozoa collected from caput, corpus, and cauda regions of the epididymis and vas deferens of rhesus monkey was measured. Spermatozoa collected from the caput epididymis have the highest concentration of zinc (36 micrograms/10(8) spermatozoa). There was a marked reduction in the zinc content of corpus spermatozoa and a further decrease in the spermatozoa of cauda epididymis. Thus the zinc content of spermatozoa gradually decreases as they migrate from the caput to cauda epididymis. There was a significant increase in the zinc content of vasal spermatozoa as compared to those collected from the cauda region of epididymis.

Animals↗

Dose dependent modulation of receptor dynamics and uterine growth in immature rat by estradiol: importance of an additional nuclear binding at 24 hr for long-term (72 hr) uterine growth.

Administration of a low dose of estradiol (0.25 or 2.5 microgram/animal) to immature rats caused a pulsatile receptor translocation, resulting in a single nuclear receptor peak (1-3 hr) and maintenance of the uterine growth until 24 hr. At a higher dose (10.0 microgram/rat), maintaining the circulatory estradiol levels for a longer duration, a biphasic nuclear translocation occurred. The usual profile of nuclear receptor binding until 12 hr was followed by a second phase of receptor translocation, resulting in an additional nuclear receptor peak at 24 hr. The uterus continued to grow until 72 hr, reaching five times its original wet weight. The duration of receptor interaction and the magnitude of uterine stimulation would, therefore, appear to be largely dependent upon the period of bioavailability of estradiol. However, there are additional intracellular regulatory mechanisms not fully understood as yet, which seem to modulate the cytosol-nuclear receptor dynamics, thus influencing the extent of uterine stimulation.

Animals↗

Kinetics of distribution and retention of 3H-oestradiol-17 beta in rat tissues: a comparative study with free oestradiol and after its incorporation into liposomes.

With a view to impart selective uptake of estrogen by the target tissues of rat, liposomes in which (6,7-3H) oestradiol-17 beta constituted a part of lipid bilayer were used as carriers of the hormone. The distribution and retention of the radioactivity was determined in blood plasma, uterus, liver, kidney, spleen and leg muscle of ovariectomized rat at different time intervals up to 72 hr following a single intravenous injection of free oestradiol (1.61 muCi) or an equivalent amount of liposomal-oestradiol. When free oestradiol was administered, uterus showed peak amount of radioactivity between 30 min to 2 hr and remained high up to 6 hr. In the other tissues examined, maximum amount of radioactivity was seen at 15 min followed by a marked fall at 30 min and also at other subsequent intervals. The pattern of uptake and retention of radioactivity after administration of liposomal-oestradiol was not much different from that of free oestradiol between 1 and 6 hr. A moderate increase in the amount of radioactivity in the nongenital tissues at 24 hr was the only difference noticed with liposomal-oestradiol. It is concluded that targeting of oestradiol preferentially to the uterus could not be achieved through liposomal delivery system.

Animals↗

Isaptent--a new cervical dilator.

A new cervical dilator, Isaptent, was prepared from granulated Plantago ovata (Isapgol) seed husk. It was evaluated in a multicentric clinical trial for dilatation of the cervix in subjects opting for medical termination of pregnancy. The trial covered 804 women in over 21 centres in different parts of the country. The cases were between 15 to 45 years of age, 0 to 10 parity with a gestation period of 8 to 24 weeks. A single tent was used in 750 subjects and satisfactory dilatation was achieved in 94% of the cases. The cervical dilatation bore no relationship to age, parity and gestation period of the subjects. The tent provided self-lubrication, caused no apparent damage to the cervix and the vaginal flora remained unchanged in the randomly selected subjects in whom bacteriologic studies were performed. The outcome of the clinical trial and advantages of Isaptent over the other procedures used for cervical dilatation are discussed.

Abortion, Induced↗

Regulation of epididymal function and sperm maturation--endocrine approach to fertility control in male.

The structural and functional integrity of the epididymis, the acquisition of fertilizing ability by spermatozoa and their viability within the epididymis are androgen dependent phenomena. Although the precise mechanism by which sperm maturation and viability in the epididymis are brought about by androgen are not clearly understood, it is generally held that specific epididymal secretions produced under the influence of androgen affect these events. Though the spermatozoa appear to remain viable in a low androgen environment, sperm maturation requires a relatively high androgen environment. Against this background the potentiality of antiandrogens as extragonadal antifertility agents has been discussed. Studies with steroidal and nonsteroidal antiandrogens have revealed that in adult animals the secretory activity of the epididymis, as evidenced by the level of glycerylphosphorylcholine, either remains unaffected or is stimulated under their influence. These studies have further indicated that the extragonadal antifertility action of antiandrogens will depend upon their ability to (1) lower the testicular androgen synthesis and/or androgen binding protein, which possibly serves as a carrier of androgen from the testis to epididymis; (2) to lower local androgen synthesis as a result of reduced levels of circulating androgen, and (3) to inhibit 5 alpha-reduction of testosterone to dihydrotestosterone and/or to inhibit androgen binding to receptors. Success in the rational development of new antifertility agents for male which will act by controlling epididymal function will depend upon a clear understanding of the factors that regulate epididymal secretion and the role of epididymal secretions in sperm maturation and survival.

Androgen Antagonists↗

Androgenic control of epididymal function in rhesus monkey and rabbit.

The effects of castration and testosterone replacement therapy on the histology and biochemical composition (RNA, DNA, total protein, alkaline phosphatase, acid phosphatase, hyaluronidase, sialic acid, glycogen, phospholipids, and glycerylphosphorylcholine [GPC]) of the epididymis of the rabbit and rhesus monkey were investigated. Castration produced marked ponderal, histologic, and biochemical changes in the epididymis. In the androgen-deficient state the tubular diameter and epithelial cell height were reduced and there was an increase in interbular stroma. The levels of RNA, DNA, phospholipids, and GPC were also reduced in castrated animals. Testosterone treatment restored the histologic features and the levels of various biochemical constituents to a great extent but not to the intact control level. The importance of endocrine and exocrine factors of the testis in relation to epididymal function is discussed.

Alkaline Phosphatase↗

Functional maturation of the epididymis in the rat.

Weight, histological and biochemical changes in the rat epididymis were investigated during prepubertal, pubertal and postpubertal periods. The phase of most rapid growth of the epididymis commenced at 21 days and extended to 60 days of age; this period corresponded closely to the onset of androgen production at 3 weeks and stabilization of the leydig cell number at 60 days. Histological differentiation in the caput epididymis started before sperm entry and was complete in the cauda only several days after the spermatozoa had appeared. The presence of appreciable quantities of glycerophosphorylcholine (GPC) and sialic acid in the epididymis of 21-day-old rats suggested inherent secretory ability of the epididymal epithelium. The concentrations of GPC, sialic acid, phospholipids and glycogen in the epididymis gradually increased with age, but each came under the influence of androgen at a different age. There was no evidence to suggest that the presence of spermatozoa has a stimulatory effect on the epididymis. Maximal secretory activity of the epididymis became established only by 90 days of age.

Animals↗

Functional maturation of the epididymis in rabbit and rhesus monkey.

The changes in the weight, histology and biochemical composition of the epididymis (caput, corpus and cauda segments) in prepuberal rabbit and rhesus monkey in response to testosterone treatment were investigated. The increase in the weight of the organ was accompanied by increased levels of RNA and DNA. Androgen therapy caused an increase in the concentration of sialic acid, phospholipids and glycerylphosphorylcholine and activities of alkaline phosphatase, acid phosphatase and hyaluronidase. The cauda region of the epididymis exhibited relatively higher levels of sialic acid and glycerylphosphorylcholine. These findings are discussed in relation to the functional maturation of the organ and the role of androgen in this process.

Acid Phosphatase↗