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Biomedical subjects

A R Sheth

Publications and source records attributed to A R Sheth.

At least 199 records · Page 11Linked to original sources
PubMed1978

Influence of bromoergocryptine on estrogen-modulated prolactin receptors of mouse mammary gland.

Modulation of specific binding of prolactin to murine mammary gland as a response to treatment with various doses of estradiol benzoate (EB) was studied. Measurements of serum and pituitary levels of prolactin were also carried out simultaneously. Estradiol benzoate at a dose of 5 microgram significantly increased the binding of 125I-labelled rat prolactin (rPRL) to mammary gland concomitant with increased serum prolactin levels in ovariectomized mice. Administration of bromoergocryptine along with EB resulted in decreased serum prolactin levels as well as binding of prolactin to breast tissue. It thus appears that the influence of estradiol on binding of prolactin to mammary gland is mediated primarily via its property of enhancing serum prolactin concentration apart from its possible direct effect at the target tissue level.

Animals↗
PubMed1978

Effect of prolactin on tetracycline binding to human spermatozoa.

The effect of different concentrations of prolactin (0 to 60 ng) on the release of tetracycline from human spermatozoa labeled with 7-3H-tetracycline hydrochloride was studied. Prolactin significantly enhanced the release of bound tetracycline, indicating that prolactin may influence the processes associated with sperm capacitation.

Cyclic AMP↗
PubMed1978

Normalization of visual fields following bromocriptine treatment in hyperprolactinemic patients with visual field constriction.

Two patients with galactorrhea-amenorrhea and bilateral visual field defects were studied. Routine radiologic examination of each patient revealed a normal sella turcica and no demineralization of the posterior clinoid process. Serum prolactin levels were elevated (patient V. G., 80 ng/ml; patient S. R., 204 ng/ml). Within 2 months of bromocriptine therapy, the serum prolactin levels were normal (patient V. G., 12.21 ng/ml; patient S. R., 8.25 ng/ml) and the bilateral visual field defects were corrected. Bromocriptine has been shown to control prolactin secretion in patients with prolactin-secreting pituitary tumors. Normalization of restricted visual fields following bromocriptine therapy indicates the possibility of an anatomical regression of pituitary hyperplasia or an underlying prolactin-producing microadenoma. It is speculated that the modality of functional galactorrhea reflects hyperplasia of the lactotrophs preceding a nodular and ultimately an adenomatous change. The continuous and prolonged administration of bromocriptine may prevent such a progressive sequence. Further experience is required to validate this possibility.

Adult↗
PubMed1978

Developmental changes in the response of male and female rat pituitary to LH-RH in vitro.

Changes in the binding of 125I-LH-RH and the sensitivity of male and female rat pituitary of LH-RH were measured in vitro from the 5th to 60th day of age. Pituitaries of all the age groups were responsive to LH-RH. Two phases of pituitary sensitivity to LH-RH could be detected in both the male and female rat. The first phase or the period of low sensitivity extended up to the day 14, while the second one or the period of high sensitivity started from the day 15 onwards. During the second period the sensitivity of female pituitary to LH-RH was significantly higher than that of male one. In the female pituitary the changes in the sensitivity to LH-RH were parallel to changes in 125I-LH-RH binding. However, in the male pituitary 125I-LH-RH binding was higher while the sensitivity of pituitary to LH-RH was compatively lower than in the female rat. It is postulated that two different types of receptors may be involved in the stimulation of LH-RH induced LH release from the male and female pituitary.

Aging↗
PubMed1977

Ectopic production of human placental lactogen by human breast tumors.

Serum samples from 72 patients with established carcinoma of the breast were investigated for ectopic presence of hPL. Further, the relationship of ectopically-secreted hPL and hCG-beta in breast cancer was investigated. Ten of 72 patients examined had detectable hPL and 12 had detectable hCG-beta, at 1-2 ng/ml serum sensitivity of the assay. The presence of hPL in serum of breast cancer patients was found to be independent of that of hCG-Beta. Sera of 13 patients with cystic mastitis, five with fibroadenoma, two with acute inflammation of breast, 20 normal women (non-pregnant) and 20 normal men did not show any detectable serum hPL or hCG-beta at the above mentioned sensitivity of the assay. Since these hormones were not detectable in normal men, normal non-pregnant women, and in patients having other pathological conditions of breast, the possible use of them as markers in cancer is expected

Adult↗
PubMed1977

Effect of neonatal testosterone and oestradiol treatment on the development of the hypothalamo-hypophysial axis in the female rat.

The hypothalamic LH-RH content and the concentrations of pituitary and plasma LH were measured at various ages in female rats treated daily with 10 micrograms testosterone propionate or 10 micrograms oestradiol-17beta from birth to Day 15. Persistent vaginal oestrus was induced in all the treated rats. Both hormones significantly reduced the hypothalamic LH-RH content and pituitary and plasma LH concentrations. Hypothalamic LH-RH increased after cessation of treatment but pituitary LH did not return to normal levels. Plasma LH levels were significantly lower than those in control rats. It is concluded that testosterone propionate and oestradiol-17beta (1) have a direct negative feed-back influence on the hypothalamus in the neonatal female rat; (2) alter the normal pattern of plasma and pituitary LH in developing female rats; (3) prevent the cyclic secretion of plasma LH after maturity; and (4) probably cause a chronic impairment in the release of LH-RH.

Animals↗