Release of immunoreactive luteinizing hormone (LH) from rat hypothalamus-pars tuberalis explants.

A luteinizing hormone (LH)-like molecule has been described in the rodent central nervous system and has been shown to have immunologic, chromatographic, and biologic activity similar to that of pituitary LH. In this communication we report that a depolarizing stimulus, high potassium concentration in the presence of calcium, causes in vitro release of LH from hypothalamic explants containing the pars tuberalis. Release from other brain areas containing LH was not seen nor was release of LH, in vitro, significantly provoked from dorsal segments of the hypothalamus, thus suggesting that most, if not all, of the releasable LH from intact hypothalamic explants may come from cells of the pars tuberalis.