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Biomedical subjects

B D Murphy

Publications and source records attributed to B D Murphy.

102 records · Page 6Linked to original sources
PubMed1977

Progestins of mink gestation: the effects of hypophysectomy.

Progesterone and 20alpha-hydroxypregn-4-ene-3-one (20alpha-ol) were determined from plasma samples taken weekly beginning 10 - 18 days before implantation in Pearl variety mink. Progesterone was low ( less than 8 ng/ml) until approximately five days prior to implantation when it increased and remained elevated (congruent to 30 ng/ml) through the early portion of postimplantation pregnancy. A subsequent decline was observed toward parturition. Mean concentrations of 20alpha-ol were relatively constant through gestation with a trend toward a greater proportion of progestin represented as 20alpha-ol during the preimplantation delay. Hypophysectomy prevented implantation, reduced progesterone levels and increased the concentration of 20alpha-ol relative to progesterone in plasma. These data suggest that prolactin (PRL) is a component of the luteotrophic complex in mink. Further, the corpus luteum of delay requires hypophyseal support for normal function.

20-alpha-Dihydroprogesterone↗
PubMed1976

Cells of the adenohypophysis of the mink (Mustela vison) identified by immunohistochemical and functional criteria.

Six cell types were described in the adenohypophysis of the mink, and a putative function was assigned to each type. These cells are the two types of gonadotrophic cells, a thyrotrophic hormone (TSH) cell, a somatotrophic (STH) cell, a prolactin (PRL) cell and a corticotrophin-producing (ACTH) cell. Gonadotrophic cells were identified by an immunolocalization technique using antisera to ovine LH. TSH cells and ACTH cells were identified by ablation of respective target organs and observation of the subsequent hypertrophic cells in the pituitary, as well as comparison with published descriptions in other species. STH cells were identified by comparison with published reports. PRL cells were observed in lactating animals and animals in lactational withdrawal.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

[45 kDa fragment of the kinesin molecule possesses high ATPase activity and binds to microtubules].

Kinesin is a mechano-chemical ATPase capable to move particles along microtubules and microtubules along the solid substrate. Molecule of bovine brain kinesin is a heterotetrameric unit consisting of two heavy (120 kDa) and two light (62 kDa) chains. We used limited proteolysis to study the location of the functional sites on the kinesin molecule. Chymotrypsin cleavage produced a stable 45 kDa fragment of the heavy chain which was purified from the digest using FPLC chromatography on a Superose 12 column. 45 kDa fragment contained both a microtubule-binding site and a ATPase site of the kinesin molecule. Cleavage of the 45 kDa fragment from the rest of the heavy chain significantly activated its ATPase activity. However, this activity remained fully dependent on microtubules. We suggest that the chymotrypsin cleavage uncouple ATPase activity of kinesin (found in the 45 kDa fragment) from its translocator activity (which, probably, required the presence of other parts of the molecule).

Adenosine Triphosphatases↗