VASOTOCIN BIOSYNTHESIS BY CULTURED PINEAL GLANDS FROM ADULT MALE RATS

Institute of Endocrinology, Bucharest, Romania (Received 20 September 1977) We have previously reported that the pineal gland of the mammalian foetus, which comprises mainly specialized secretory ependymal cells (Anderson, 1965), synthesizes the nonapeptide arginine-vasotocin (AVT; Pavel, Dorcescu, Petrescu-Holban & Ghinea, 1973; Pavel, Goldstein, Ghinea & Calb, 1977). However, in contrast with the foetal pineal gland, the predominant cell type in the pineal gland of the adult mammal is the parenchymal cell or pinealocyte (Quay, 1965); there is a marked reduction in the number of ependymal cells and they are restricted to the pineal recess (Anderson, 1965), which shows the same secretory characteristics as the subcommissural organ (Palkovits, 1965). Since we have postulated the ependymal origin of mammalian AVT (Pavel, 1971; Pavel et al. 1973; Pavel, 1975; Pavel et al. 1977), it seemed worthwhile to investigate the synthesis of AVT in the adult pineal gland in order to elucidate, if only

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Effects of Melatonin and Natural and Synthetic Analogues of Arginine Vasotocin on Plasma Prolactin Levels in Adult Male Rats

Hormone Research ◽

10.1159/000178917 ◽

1978 ◽

Vol 9 (4) ◽

pp. 236-246 ◽

Cited By ~ 13

Author(s):

Mary K. Vaughan ◽

John C. Little ◽

Linda Y. Johnson ◽

David E. Blask ◽

George M. Vaughan ◽

...

Keyword(s):

Adult Male ◽

Arginine Vasotocin ◽

Male Rats ◽

Plasma Prolactin ◽

Synthetic Analogues ◽

Natural And Synthetic

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Role of the Pineal Gland in Growth Restraint of Adult Male Rats by Light and Smell Deprivation

Neuroendocrinology ◽

10.1159/000121999 ◽

1971 ◽

Vol 8 (2) ◽

pp. 116-124 ◽

Cited By ~ 19

Author(s):

Sandy Sorrentino, Jr. ◽

Russel J. Reiter ◽

Don S. Schalch ◽

Robert J. Donofrio

Keyword(s):

Pineal Gland ◽

Adult Male ◽

Male Rats

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Influence of pinealectomy on the suppression of gonadotrophin secretion induced by hyperprolactinaemia in the adult male rat

Journal of Endocrinology ◽

10.1677/joe.0.0970401 ◽

1983 ◽

Vol 97 (3) ◽

pp. 401-407 ◽

Cited By ~ 4

Author(s):

A. S. McNeilly ◽

D. W. Lincoln

Keyword(s):

Pineal Gland ◽

Adult Male ◽

Male Rats ◽

Male Rat ◽

Gonadotrophin Secretion ◽

Adult Male Rat ◽

Pituitary Glands ◽

Hypothalamic Pituitary Axis

To investigate the role of the pineal gland in the long-term suppression of gonadotrophin secretion induced by prolactin, the effects of pinealectomy were studied in adult male rats with hyperprolactinaemia produced by the transplantation of two pituitary glands under the kidney capsule. Pinealectomy had no effect on basal levels of LH, FSH or prolactin. The presence of pituitary transplants induced a significant twofold increase in prolactin levels and a prolonged suppression in both LH and FSH. These changes were not affected by pinealectomy. Castration resulted in a similar rise in plasma levels of LH and FSH in rats with and without pituitary transplants. In control rats this rise in LH and FSH was reduced by testosterone-containing silicone elastomer implants (s.c) of 10 mm in length and delayed by implants of 30 mm. These rises in LH and FSH were significantly delayed (10-mm implant) or abolished (30-mm implant) in rats with pituitary transplants indicating an increase in sensitivity of the hypothalamic-pituitary axis to the negative feedback effects of testosterone in these animals compared to controls. These responses were not affected by pinealectomy. These results suggest that the pineal gland is not involved in the mechanism whereby pituitary grafts, possibly through their secretion of prolactin, cause long-term suppression of gonadotrophin secretion.

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