A New Apparatus for Pituitary Stalk Section in the Rat

Abstract

The many discrepancies in the results of experiments on pituitary stalk section, reported in the literature, are almost certainly due in part to the great difficulties involved in the performance of this operation. Therefore, we have thought it of some interest to give a detailed description of a relatively simple apparatus devised for this purpose and which has been used by one of us with good results since 1940.For much of its course, the pituitary stalk lies in direct contact with the basisphenoid and is thus relatively easy to reach, if approached from the base of the skull. Nevertheless, the use of the classical parapharyngeal route universally adopted for hypophysectomy in the rat meets with almost insuperable difficulties as regards obtaining a good view of the pituitary stalk, which is located too far anteriorly, and the operation so conducted remains a blind operation.For this reason, without rejecting the ventral approach through the base of the skull, which has proved so useful for avoiding cerebral lesions during hypophysectomy, we deliberately omitted the preliminary steps for exposure of the pituitary in order to see the stalk, and we preferred to locate the latter with the aid of external bone landmarks.The landmarks we use are the classical ones for hypophysectomy, namely, the transverse line forming the synchondrosis between the basisphenoid and the basioccipital on the one side and the median crest of the basioccipital on the other. The former can be taken as an indication of how far anteriorly we should penetrate into the skull ; the latter gives the median line of the skull, on a prolongation of which the point of penetration into the cranial cavity must fall.A preliminary study of camera lucida drawings of saggital sections of the skull including pituitary and brain enables the position of an oblique line passing through the pituitary stalk, and the angle it should make with the base of the skull, to be determined. It is also easy to see where the synchondrosis between the basisphenoid and the basioccipital will project on to this line when seen under the binocular loupe with a given inclination. If we imagine this line replaced by an electrolytic needle with a mark corresponding to this projection, the skull being maintained in a fixed position, it will suffice to make the mark coincide with the synchondrosis, in the midline of the skull as indicated by the median crest of the basioccipital, and the needle will then meet the pituitary stalk.The problem is to devise an apparatus immobilizing the base of the skull in a fixed position and carrying an electrolytic needle which should penetrate the base of the skull at a given angle. This angle is chosen to accommodate small individual variations

Effect of Reserpine on Pituitary Prolactin Content and Its Hypothalamic Site of Action in the Rabbit

“…Earlier studies of the effects of hypothalamic lesions on activation of the mammary glands in rabbits (Haun 8c Sawyer 1960 were initiated in search of an explanation of the mechanism by which reserpine stimulates lactation. The results of those studies and others (McCann 8c Friedman 1960; Grosz 8c Rothballer 1961) were consistent with the hypothesis of Desclin (1950) and Everett (1956) who proposed that the secretion of prolactin from the pituitary gland is held chronically in check by the hypothalamus. Prolactin assays of the pituitary glands revealed that effective hypothalamic lesions lower the pituitary prolactin content and suggested that the intact hypothala¬ mus chronically inhibits release rather than synthesis of prolactin ).…”

The cytochemical demonstration of gonadotropic hormone in the human anterior hypophysis

“…The granules of the basiphils retain their affinity for the basic dyes after conversion of their carbohydrate by periodic acid and its fixation by leuco-fuchsin, part of this being due to the strongly dissociated acid groups of nucleoprotein which remain intact. This nucleoprotein (ribonucleic acid) is removable by hydrolysis with ribonuclease, as shown by Desclin (1940), and the true /3 granules which remain are no longer strongly basiphil. They are still P.A.S.-positive but are now less basiphil than the a granules, staining only faintly after 24 hours in 5 x 10 M methylene blue at pH 6.4, whereas the a granules are deep blue at this pH.…”

Studies on the Hormonal Induction of Mammary Growth and Lactation in the Goat

“…These studies up to 1947 have been reviewed by Malpress [1947]. Since that time further studies have been made on the bovine [Dyrendahl, 1946;Hohlweg, 1947Hohlweg, , 1949Hohlweg & Spierling, 1947 ;Marshall, Becker, Dix Arnold & Sanders, 1948;Nottbohm, 1948;Langheinrich, 1949 ;Letard, Szumowski & Parez, 1949 ;Peeters, Massart, Coussens & Vandeplassche, 1949;Szumowski & Langlois, 1949;Trautmann, 1949], horse [Peeters, Vandeplassche & Massart, 1946], sheep [Peeters & Massart, 1947], goat [Trautmann, 1949;Desclin & Derivaux, 1950; Roy, Bhattacharya, Luktuke & Bhattacharya, 1950] and pig [Trautmann & Fauvet, 1947].…”