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Biomedical subjects

B L Hart

Publications and source records attributed to B L Hart.

At least 109 records · Page 6Linked to original sources
PubMed1980

Objectionable urine spraying and urine marking in cats: evaluation of progestin treatment in gonadectomized males and females.

The increasing use of long-acting progestins to treat objectionable urine spraying and urine marking in gonadectomized cats prompted a survey of the comparative effectiveness of the injectable medroxyprogesterone acetate (MPA) and the orally administered megestrol acetate (MA). Both drugs were successful, overall, in about 1/3 of the patients. However, the proportion with favorable response was higher for males (48%) than for females (13%) and was higher for cats from single-cat homes (50%) than for cats from multi-cat homes (18%). Because of the reportedly higher frequency of depression and increased appetite following MA treatment, when compared with MPA treatment, it is recommended that MPA be used initially for routine treatment of these behavioral problems. The survey revealed that if MPA proves ineffective, subsequent treatment with MA can be expected to yield favorable results in some of these patients.

Administration, Oral↗
PubMed1980

Flehmen and vomeronasal organ function in male goats.

The possible role of flehmen behavior in facilitating the passage of non-volatile materials from the oral cavity to the vomeronasal organ (VNO) was studied by the use of a tracer dye, sodium fluorescein. The dye was applied to the oral cavity of six male goats in which flehmen was elicited by the presentation of female urine. Immediately afterwards a lethal dosage of anesthetic was given and the maxilla, including the VNO, was removed, frozen, and cut into transverse sections. Seven control subjects were treated similarly but were not stimulated to display flehmen. Examination of transverse sections under ultraviolet illumination revealed dye in the posterior part of the VNO in most subjects that performed flehmen but only in the anterior part of the VNO of subjects that did not perform flehmen. Inasmuch as only the middle and posterior parts of the VNO contain sensory epithelium, it was concluded that, if the dye represented a behaviorally significant non-volatile material (sex attractant), only the goats that showed flehmen would have detected the material from VNO chemoreception.

Animals↗
PubMed1980

Accelerated and enhanced testosterone secretion in juvenile male dogs following medial preoptic-anterior hypothalamic lesions.

Lesions of the medial preoptic-anterior hypothalamic (MP-AH) continuum made in juvenile male dogs (10-11 weeks of age) were previously reported to reduce juvenile mounting and virtually eliminate male copulatory behavior in adulthood. The effects of these lesions on the developmental patterns of serum testosterone (T) and luteinizing hormone (LH) were examined in the present study. Subjects with MP-AH lesions (MP-AH subjects) had a pubertal rise in serum T almost 2 months before subjects with sham lesions (SHAM subjects). Subsequently mean serum T of MP-AH subjects rose to levels significantly higher than those of SHAM subjects before falling back to the normal 3-4 ng/ml range of SHAM subjects at 10 months. There was no apparent relationship between secretion of LH and the acceleration and enhancement of serum T. These observations indicate that there can be impairment of male sexual behavior with lesions that accelerate and enhance sexual functioning in other respects.

Animals↗
PubMed1980

The effect of somatostatin on the intestinal transport of glucose in vivo and in vitro in the rat.

The possibility that somatostatin has a direct inhibitory effect on intestinal D-glucose absorption was studied in rats using intact intestinal loops and everted jejunal segments. Somatostatin infusion in vivo produced a significant fall in plasma glucose concentration (P less than 0.001) and a fall in pooled plasma insulin concentration to 51% of control values. However, somatostatin infusion did not alter significantly from control values the rate of glucose disappearance from the perfused jejunal lumen in vivo or the appearance of gut-derived plasma glucose. The lack of an inhibitory effect of somatostatin on glucose absorption in vivo was confirmed using two in vitro studies. When increasing concentrations of somatostatin (0-10(4) ng/ml-1) were added to both mucosal and serosal solutions, no significant differences were seen for net transmural flux or unidirectional flux of D-glucose in everted jejunal segments. These studies suggest that somatostatin in the rat does not influence plasma glucose concentration by inhibiting intestinal glucose transport at physiological concentrations of glucose and over a wide range of somatostatin concentrations.

Animals↗
PubMed1979

Activation of sexual reflexes of male rats by dihydrotestosterone but not estrogen.

Previous studies have shown that withdrawal and administration of testosterone propionate (TP) has a quantitative influence on sexual reflexes which parallels changes in copulatory activity following castration and administration of TP. The present study involving castrated spinal male rats explored further this parallel, focusing on the effects on sexual reflexes of the administration of dihydrotestosterone propionate (DHTP) and estradiol benzoate (EB), both of which can activate sexual behavior in spinally intact castrated male rats, but only if given in very large doses for a prolonged period of time. A parallel effect on reflexes and behavior was not found inasmuch as DHTP activated sexual reflexes at a dose (200 microgram daily) considerably below that needed to activate behavior, and EB did not appreciably activate reflexes, even after prolonged treatment at levels (100-200 microgram) higher than necessary to activate behavior. The results, with EB in particular, point out that the display of intromissive and ejaculatory patterns in rats may not involve spinal neural mechanisms that are customarily associated with these behavioral patterns.

Animals↗
PubMed1979

Effects of medial preoptic-anterior hypothalamic lesions on development of sociosexual behavior in dogs.

Bilateral medial preoptic-anterior hypothalamic lesions in adult male dogs eliminate or impair copulatory behavior and reduce urine-marking responses but do not affect aggressive behavior. The present study examined the emergence of the adult forms of these same male sociosexual behavioral patterns when the lesions are made prior to puberty. The subjects were allowed to interact with male peers during development. Animals with lesions had reduced frequence of juvenile mounting and an almost total absence of male copulatory activity in adulthood. Urine-marking and aggressive behavior in the juvenile and adult periods were not affected by the lesions. The findings reveal a sparing of function with regard to urine-marking but not sexual behavior.

Aggression↗