These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Nutritional modification of rat heart postnatal development.
    Author: Dowell RT.
    Journal: Am J Physiol; 1984 Mar; 246(3 Pt 2):H332-8. PubMed ID: 6703071.
    Abstract:
    Postnatal development of the mammalian myocardium encompasses increases in cellularity, energy producing and energy utilizing systems, and concurrent augmentation of heart contractile performance. The present study disrupted normal developmental sequences by adjusting the number of newborn rats per litter at 4 days postbirth. Fast-growing (4 rats/litter), normal (8 rats/litter), or slow-growing (16 rats/litter) animals were studied when 21 days old. Left ventricular cellularity (total DNA) increased as a function of the nutritionally modified growth of the heart, having values of 562 +/- 27, 625 +/- 33, and 791 +/- 20 (SE) micrograms in 16, 8, and 4 rats/litter groups, respectively. Low levels of systolic pressure (55 + 5 mmHg) and rate of pressure development (dP/dt, 2,670 +/- 130 mmHg/s) were noted in the slow-growing rats. Growth-related augmentation of pressure and dP/dt occurred such that adult levels (104 +/- 4 mmHg; 5,810 +/- 290 mmHg/s) were observed in 21-day-old, fast-growing rats. An enzymatic marker for aerobic metabolism (malate dehydrogenase) indicated mitochondrial accumulation in excess of ventricular tissue, thereby establishing progressive increases in aerobic capacity. Myofibrillar ATPase activity was not significantly different among all groups. Thus heart contractile function during nutritionally induced changes in postnatal development is augmented in proportion to increases in heart DNA content. A positive relationship also exists between dP/dt and number of mitochondria; however, enhanced contractile function is achieved independently of myofibrillar ATPase activity level.
    [Abstract] [Full Text] [Related] [New Search]