Hypophysectomized Rats Depend on Residual Prolactin for Survival*

Abstract

Hypophysectomized (Hypox) female Fischer 344 rats had 10-20% lactogenic activity in their serum when compared to controls by the Nb2 lymphoma proliferation assay. If such animals were treated daily with a rabbit antirat PRL serum, their serum lactogenic activity diminished further; severe anemia and immunological anergy developed; and death occurred within 8 weeks. In contrast, untreated Hypox animals increased gradually their serum lactogenic activity, starting on the 7th week after pituitary removal, which rose up to 50% of control levels by week 9. Hypox animals showed normochromic normocytic anemia, a grossly reduced immunocompetence, decreased body, thymus, spleen, adrenal, and ovary weights, and decreased DNA and RNA synthesis in the thymus, spleen, and bone marrow. However, the condition of Hypox animals did not deteriorate further over the 9-week experimental period. All the hematological deficiencies and decrease in organ weights observed in Hypox rats were normalized after grafting with syngeneic pituitaries (SPG). These effects of SPG could be inhibited by additional treatment with antirat PRL serum. Treatment of Hypox animals with ovine PRL had a restoring effect similar to SPG, which was not inhibited by additional antirat PRL serum treatment. Rat and ovine PRL and GH and human placental lactogen all stimulated the incorporation of 3H-thymidine by rat bone marrow cells in vitro. These results indicate that PRL has a multiple trophic effect and is capable of maintaining vital bodily functions for long periods of time.

Prolactin receptor signal transduction in cells of the immune system

“…Similar to other ILs, PRL acts as a necessary co-mitogen during lymphoid expansion. An immunomodulatory role for PRL was first identified in avian and murine species, secondary to in vivo manipulation of serum PRL levels (Berczi et al 1981, Nagy et al 1983, Glick 1984, Nagy & Berczi 1991. Subsequent in vitro studies have found that in the presence of antigen and/or mitogen, PRL acts as a necessary co-mitogen for T and B cells of human or murine origin (Russell et al 1984, Bernton et al 1988, Hartmann et al 1989, Clevenger et al 1990, Skwarlo-Sonta 1990.…”

Prolactin and the physiological regulation of its secretion. A review

“…The hypophysectomized rats, just after hypophysectomy, retain about 20% of biologically active form of PRL in blood, which increases to approximately to 50% in normal level with time (Nagy and Berczi, 1991;Bole-Feysot et al, 1998). Neutralization of circulating PRL with PRL-antibodies results in immune disfunction and death of animals indicating that extrapituitary PRL can compensate for pituitary PRL (Nagy and Berczi, 1991).…”

“…Neutralization of circulating PRL with PRL-antibodies results in immune disfunction and death of animals indicating that extrapituitary PRL can compensate for pituitary PRL (Nagy and Berczi, 1991).…”

Altered expression of receptors for thyroid hormone and insulin-like growth factor-1 during reconstitution after allogeneic hematopoietic stem cell transplantation

“…1-5 g of the total RNA preparation was diluted in DEPC treated water to a volume of 8 l and denaturated for 10 min at 65°C. The RNA solution was mixed with 5 l Bulk Reaction mix (containing reverse transcriptase, bovine serum albumin (BSA) and dNTPs), 1 l dithiothreitol (DTT), and 1 l random hexadeoxynucleotide primer (pd(N) 6 ). The mixture was incubated for 1 h at 37°C.…”

“…1 Studies in animal models have shown that these two neuroendocrine hormones are important for hematological activity, but since the models analyzed are deficient in several hormones, the importance of each hormone can not be fully determined. 5,6 GH has been suggested to have an immunomodulatory effect on development, maintenance and function of the immune system. [7][8][9] GH deficiencies in humans do not, however, present as clinically significant hematological deficiencies.…”