Effect of prolactin and growth hormone on prolactin and LH receptors in the dwarf mouse

Abstract

Dwarf mice (DW/J; dw/dw) which exhibit a deficiency of prolactin and GH secretion were treated for 8 days with ovine prolactin and/or human GH (10 or 20 \g=m\g/day) and the effect on hepatic and testicular prolactin receptors was investigated. In both sexes there was a significant increase in body weight after all hormone treatments, but an increment in testicular weight was observed only after prolactin administration. Prolactin treatment increased the specific binding % of prolactin in liver membranes in females but not males, and in testicular homogenates (together with an increase in LH receptors). The results suggest that lack of prolactin but not of GH retards sexual development in these mice. Treatment with prolactin partly counteracts this deficiency, and the effect may be mediated by the induction of hepatic and testicular prolactin and LH receptors.

Development of the seminiferous tubules after neonatal hemicastration in the boar

“…However, plasma concentrations of prolactin were related to the onset of spermatogenesis rather than as a result of hemicastration. The mechanism by which prolactin influences early pubertal Sertoli cell function and spermatogenesis, although unclear, appears to be by indirectly influencing the receptiveness of Leydig cells to LH stimulation and androgen secretion (Bohnet & Friesen, 1976;Zipf et al, 1978;Stoud et al, 1985). …”

Hypoprolactinemia as Related to Seminal Quality and Serum Testosterone

“…Animal studies have demonstrated that a lack in serum prolactin is associated to a loss in testicular LH receptors and these are recovered only after treatment with prolactin [7,321. A decrease in the number of LH receptors due to hypoprolactinemia may account for diminished serum testosterone levels.…”

Ovarian membrane receptors for LH, FSH and prolactin during the menstrual cycle and in polycystic ovary syndrome.

“…The prolacin receptor is generally considered to be upward by the homologous hormone in rat liver or ovary Bohnet and Friesen 1976), which is different from regulation of LH or FSH receptors (Conti et al 1977;Ireland and Richards 1978). It is interesting that a strong negative correlation was observed between the prolactin receptor and serum FSH level.…”