ISSN:
0003-276X
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
Notes:
Single injections (8 mg/kg maternal body weight) of the niacin antimetabolite 6-aminonicotinamide (6-AN) given to rats on the morning of the fifteenth day of gestation resulted in 100% palatal abnormalities within 24 to 48 hours. Fasting rats for a period of seven or eight days, more than simulating the weight loss observed in 6-AN treated animals, resulted in young without palatal abnormalities. Simultaneous injection of an equal dosage of nicotinamide prevented the maternal and embryonic effects of the antimetabolite. Intralitter variability in normal palatal closure, similar to the interlitter variation, was observed in embryos of the same chronological age.Retardation in palatal shelf movement appeared to be the initial underlying morphological mechanism giving rise to the abnormal palates. Twenty-four hours after 6-AN injection embryonic and placental weights were significantly reduced; the incidence of full open palate was double that observed in untreated rats. Forty-eight hours following treatment palatal shelves had moved to the horizontal position dorsal to the tongue; failure of fusion was apparent. Further alterations in the morphogenesis of the abnormal palates were secondary to partial or complete failure of shelf fusion, complicated by a dorsally protruding tongue and underdeveloped mandible.The sensitivity of palatal closure between days 15 to 17 of gestation and the rapidity with which shelf movement can be delayed and modified by metabolic procedure in the rat is noteworthy.
Additional Material:
1 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/ar.1091560106
